Asteroids Archives

February 11, 2013December 23, 2015 by David Dickinson

Asteroid 2012 DA14: Observing Prospects and How to See It

Mark your calendars: this Friday, February 15, 2013, is the close flyby of Near Earth Asteroid 2012 DA14, passing just 27,630 kilometers (17,168 miles) from the surface of the Earth. About 50 meters (164 feet) in size, 2012 DA14 and its close shave marks the the first time there has been passage of an asteroid this close that we’ve known a year beforehand. Yes, it passes within the ring of geosynchronous satellites girdling the Earth. No, there’s no danger, either to said satellites or the Earth, so Bruce Willis can stay home for this one. But right behind those inquiries, the question we most frequently get is… how can I see it?

The orbital path of asteroid 2012 DA14 as seen face on (top) & near edge on (bottom). (Credit: JPL Small Body Database Browser).

The great news is that an advanced observer can indeed catch 2012 DA14 on its close pass the night of February 15^th… with a little skill and luck. Now for the bad news; the asteroid won’t be visible without binoculars or a telescope, and North America will largely miss out.

2012 DA14 will be really moving across the sky on closest approach, covering 0.8° per minute, or the diameter of a Full Moon every 45 seconds! With its passage closer to the Earth than the ring of geosynchronous satellites, it’s worth treating the passage of the asteroid as a satellite and hunting it down accordingly. Catching and watching such a pass can be an unforgettable experience; not many objects in the sky show such swift motion in real time. In fact, 2012 DA₁₄ will span the celestial sphere from declination -60° to +60° in just 4 hours! Needless to say, its passage through the Earth’s gravity well will alter its orbit considerably; most planetarium software programs do not account for this and thus will introduce a large error for a heliocentric object. Compounding the dilemma is the large amount of parallactic shift of such a nearby object. As viewed from the span of the Earth, 2012 DA14 will have a parallax of ~20° at greatest approach!

The path of asteroid 2012 DA14 through the celestial sphere on February 15th. (Created by Author).

But two sites on the web can help you with the search. One is Heavens-Above, which currently has a link on its main page to custom generate sky charts for specific locations for 2012 DA14 (make sure you’re logged in as a registered user and your observing location is set correctly). Another option is to generate an ephemeris customized for your location from the JPL Solar System Dynamics Horizons Web-Interface.

Asteroid 2012 DA14 is approaching the planet Earth from “down under,” and moving almost exactly parallel to the 12 hour line in right ascension. In fact, it’ll cross very near the equinoctial point in Virgo (one of the two points where the celestial equator and the ecliptic cross) shortly after its closest approach on Friday, February 15^th at 19:25UT. The asteroid will be at the local zenith (straight overhead) for observers in the pre-dawn hours located in western Indonesia at closest approach. Australia and eastern Asia will have a shot at seeing the asteroid as it whizzes through the sky in the early morning hours of February 16^th local. Observers in western Asia, Africa and Europe will see the asteroid lower to the east on the night of the 15^th. Note that 2012 DA14 juuuuuust misses Earth’s shadow (see strip chart) at closest approach. The shadow of our fair planet is ~20° across at the distance of the geosynchronous satellites; had it passed about a month later, we would have seen an “asteroid eclipse!” In fact, “eclipse season” for geosynchronous satellites occurs right around the equinoxes and is only a month away.

The “banana strip chart” shows the path of 2012 DA14 from the time it reaches a magnitude brighter than +10 at 17:40UT until it dips back down below it at 22:10UT on the same night. It also shows the width of uncertainty for its position due to the aforementioned 20° of parallax, and the points that it enters and departs the distance sphere of the geosynchronous satellites. Keep in mind, these satellites still orbit roughly hundred times higher than the International Space Station!

A good search strategy to catch 2012 DA14 is to actually to treat it like you’re hunting for a faint satellite. Find the time that it’s crossing a set declination and begin scanning with binoculars in right ascension back and forth until you “ambush” your astronomical prey moving slowly against the starry background. If using a telescope, use the lowest power and widest field of view that the instrument will allow. We’ve used this technique in the past to sweep up Near Earth Asteroids 2005 YU55 and 99942 Apophis and routinely use it to hunt for satellites fainter than naked eye visibility. At closest approach, asteroid 2012 DA14 will shine at around +8^th magnitude as it crosses the Bowl of Virgo northward past Denebola in the constellation Leo.

Recent measurements early this month conducted by astronomers at the Las Campanas observatory in Chile refined the orbit of 2012 DA14, placing its February 15^th passage just 45 kilometres closer to Earth than previously calculated but still well outside the threat zone. Campaigns are underway to refine measurements of its orbit even further on this pass. We won’t get another close pass of 2012 DA14 until February 16^th, 2046 when the asteroid misses us at about twice the distance of the Moon. An impact has been ruled out for this century. Predictions get less certain the further you project them into time, and 2012 DA14 will definitely be a space rock worth keeping tabs on!

January 30, 2013December 23, 2015 by Jason Major

In Two Weeks This 50-Meter Asteroid Will Buzz Our Planet

Asteroid 2012-DA14 will pass Earth closely on Feb. 15, 2013 (NASA)

On February 15 a chunk of rock about 50 meters wide will whiz by Earth at nearly 8 km/s, coming within 27,680 km of our planet’s surface — closer than many weather and communications satellites.

For those of you more comfortable with imperial units, that’s 165 feet wide traveling 17,800 mph coming within 17,200 miles. But regardless whether you prefer meters or miles, in astronomy that’s what’s called a close call.

Scientists stress that there’s no danger of an impact by this incoming asteroid, designated 2012-DA14, but it’s yet another reminder that in our neck of the Solar System we are definitely not alone.

“2012-DA14 will definitely not hit Earth,” says JPL’s near-Earth object specialist Don Yeomans. “The orbit of the asteroid is known well enough to rule out an impact.”

But with 2012-DA14’s upcoming February flyby Yeomans notes, “this is a record-setting close approach.”

The rocky asteroid will come within about 4 Earth radii, which is well within the orbits of geosynchronous satellites. During its closest approach at 19:26 UTC it should be visible in the sky to amateur telescopes (but not the naked eye), becoming as bright as an 7th- or 8th-magnitude star.

Radar observatories will be watching 2012-DA14 during the days leading up to and following its approach in an attempt to better determine its size, shape and trajectory. NASA’s Goldstone facility will have an eye — er, dish — on DA14, but it won’t be visible to Arecibo. Stay tuned for more info!

Read more about 2012-DA14 on the JPL Near-Earth Object Program page here.

January 25, 2013June 5, 2022 by Ken Kremer

NASA: Reaches for New Heights – Greatest Hits Video

Video Caption: At NASA, we’ve been a little busy: landing on Mars, developing new human spacecraft, going to the space station, working with commercial partners, observing the Earth and the Sun, exploring our solar system and understanding our universe. And that’s not even everything.Credit: NASA

Check out this cool action packed video titled “NASA: Reaching for New Heights” – to see NASA’s ‘Greatest Hits’ from the past year

The 4 minute film is a compilation of NASA’s gamut of Robotic Science and Human Spaceflight achievements to explore and understand Planet Earth here at home and the heavens above- ranging from our Solar System and beyond to the Galaxy and the vast expanse of the Universe.

Image caption: Planets and Moons in perspective. Credit: NASA

The missions and programs featured include inspiringly beautiful imagery from : Curiosity, Landsat, Aquarius, GRACE, NuSTAR, GRAIL, Dawn at Asteroid Vesta, SDO, X-48C Amelia, Orion, SLS, Apollo, SpaceX, Sierra Nevada Dream Chaser, Boeing CST-100, Commercial Crew, Hurricane Sandy from the ISS, Robonaut and more !

And even more space exploration thrills are coming in 2013 !

Ken Kremer

Image caption: SpaceX Falcon 9 rocket blasts off on May 22, 2012 with Dragon cargo capsule from Space Launch Complex-40 at Cape Canaveral Air Force Station, Fla., on the first commercial mission to the International Space Station. The next launch is set for March 1, 2013. Credit: Ken Kremer

January 11, 2013December 23, 2015 by Nancy Atkinson

Asteroid Apophis: Bigger, Darker But Not a Threat in 2036

Asteroid Apophis was discovered on June 19, 2004. Image credit: UH/IA

During its close approach this week, observatories from ESA and NASA have made some updates on their assessment of asteroid Apophis and its future encounters with Earth. While the Herschel Space Telescope observations indicates the asteroid is bigger and less reflective than first estimated, scientists at the Jet Propulsion Laboratory have effectively ruled out the possibility that this asteroid will impact Earth during a close flyby in 2036.

Repeat after me: Asteroid Apophis is not a threat to Earth in 2029 or 2036. Got that doomsday prognosticators?

Discovered in 2004, Apophis garnered lots of attention when initial calculations of its orbit indicated a 2.7 percent possibility of an Earth impact during a close flyby in 2029. Data discovered during a search of old astronomical images provided the additional information required to rule out the 2029 impact scenario, but a remote possibility of one in 2036 remained – until now.

ESA’s Herschel Space Observatory captured asteroid Apophis in its field of view during the approach to Earth on 5/6 January 2013. This image shows the asteroid in Herschel’s three PACS wavelengths: 70, 100 and 160 microns, respectively. Credit: ESA/Herschel/PACS/MACH-11/MPE/B.Altieri (ESAC) and C. Kiss (Konkoly Observatory)

Herschel provided the first thermal infrared observations of Apophis at different wavelengths, which together with optical measurements helped refine estimates of the asteroid’s properties. Previous estimates bracketed the asteroid’s average diameter at 270 ± 60 m; the new Herschel observations returned a more precise diameter of 325 ± 15 m.

“The 20% increase in diameter, from 270 to 325 m, translates into a 75% increase in our estimates of the asteroid’s volume or mass,” says Thomas Müller of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, who is leading the analysis of the new data.

By analyzing the heat emitted by Apophis, Herschel also provided a new estimate of the asteroid’s albedo – a measure of its reflectivity – of 0.23. This value means that 23% of the sunlight falling onto the asteroid is reflected; the rest is absorbed and heats up the asteroid. The previous albedo estimate for Apophis was 0.33.

Knowing the thermal properties of an asteroid indicates how its orbit might be altered due to subtle heating by the Sun. Known as the Yarkovsky effect, the heating and cooling cycle of a small body as it rotates and as its distance from the Sun changes can instigate long-term changes to the asteroid’s orbit.

Additional data from the Magdalena Ridge Observatory in New Mexico, the Pan-STARRS observatory in Hawaii and the Goldstone Solar System Radar have provided more conclusive evidence when scientists ran the numbers.

“We have effectively ruled out the possibility of an Earth impact by Apophis in 2036,” said Don Yeomans, manager of NASA’s Near-Earth Object Program Office at JPL. “The impact odds as they stand now are less than one in a million, which makes us comfortable saying we can effectively rule out an Earth impact in 2036. Our interest in asteroid Apophis will essentially be for its scientific interest for the foreseeable future.”

But the flyby on April 13, 2029 will be one for the record books, scientists say. On that date, Apophis will become the closest flyby of an asteroid of its size when it comes no closer than 31,300 kilometers (19,400 miles) above Earth’s surface.

“But much sooner, a closer approach by a lesser-known asteroid is going to occur in the middle of next month when a 40-meter-sized asteroid, 2012 DA14, flies safely past Earth’s surface at about 17,200 miles,” said Yeomans. “With new telescopes coming online, the upgrade of existing telescopes and the continued refinement of our orbital determination process, there’s never a dull moment working on near-Earth objects.”

Goldstone radar observations of Apophis will continue through January 17th, and additional tracking is planned next month with the Arecibo radio dish in Puerto Rico, which should provide even more refinements in Apophis’ orbit.

Sources: ESA, JPL

(99942) Lead video: APOPHIS sur fond d’étoiles au Pic du Midi from Francois Colas on Vimeo.

January 9, 2013January 10, 2013 by Nancy Atkinson

Watch Live Webcast of Asteroid Apophis Earth Flyby

Once again, the Slooh Space Camera team will host a live webcast of an asteroid flyby of Earth. This one might be a bit more intriguing than others, if only because of the connotation this asteroid has. Asteroid Apophis a near-Earth asteroid with an estimated diameter of almost three football fields (270m), is making its closest approach to us this year — but it will still be quite distant, at about 14 million km – but this is close enough for astronomers to study the space rock and assess its future risk.

On Wednesday, January 9th, Slooh.com, will start the webcast at 4 p.m. PST / 7 p.m. EST / 00:00 UTC (1/10) — International times here — accompanied by real-time discussions with Slooh President Patrick Paolucci, Slooh Outreach Coordinator and Engineer Paul Cox, and Documentary Filmmaker Duncan Copp.

Continue reading “Watch Live Webcast of Asteroid Apophis Earth Flyby”

January 4, 2013December 23, 2015 by Jason Major

Ancient Impacts Stained Vesta with Carbon-Rich Material

Composite-color 3D image of Cornelia crater on Vesta (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

Ever since arriving at Vesta in July 2011, NASA’s Dawn spacecraft has been capturing high-resolution images of the protoplanet’s surface, revealing a surprisingly varied and complex terrain covered in ridges, hills, grooves and, of course, craters of many different sizes and ages. Many of Vesta’s largest craters exhibit strange dark stains and splotches within and around them, some literally darker than coal. These stains were a puzzle to scientists when they were first seen, but the latest research now confirms that they may actually be the remains of the ancient impacts that caused them: dark deposits left by the myriad of carbon-rich objects that struck Vesta over the past four-and-a-half billion years.

Even though Vesta had a completely molten surface 4.5 billion years ago it’s believed that its crust likely solidified within a few million years, making the 530-km (329-mile) -wide world a literal time capsule for events taking place in the inner Solar System since then… one reason why Vesta was chosen as a target for the Dawn mission.

Using data acquired by Dawn during its year in orbit around Vesta, a team led by researchers from Germany’s Max Planck Institute for Solar System Research and the University of North Dakota investigated the dark material seen lining the edges of large impact basins located on the protoplanet’s southern hemisphere. What they determined was that much of the material was delivered during an initial large, low-velocity impact event 2–3 billion years ago that created the largest basin — Veneneia — and was then partially covered by a later impact that created the smaller basin that’s nearly centered on Vesta’s southern pole — Rheasilva.

“The evidence suggests that the dark material on Vesta is rich in carbonaceous material and was brought there by collisions with smaller asteroids.”

– Vishnu Reddy, lead author, Max Planck Institute for Solar System Research and the University of North Dakota

Dawn framing camera images of dark material on Vesta. (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

Subsequent smaller asteroid impacts over the millennia likely brought more carbonaceous material to Vesta’s surface, both delivering it as well as revealing any that may have existed beneath brighter surfaces.

The dark, carbon-rich material observed on Vesta by Dawn also seems to match up with similarly dark clasts found in meteorites that have landed on Earth which are thought to have originated from Vesta.

“Our analysis of the dark material on Vesta and comparisons with laboratory studies of HED meteorites for the first time proves directly that these meteorites are fragments from Vesta,” said Lucille Le Corre from the Max Planck Institute for Solar System Research, another lead author of the study.

If evidence of such collisions between worlds can be found on Vesta, it’s likely that similar events were occurring all across the inner solar system during its early days, providing a clue as to how carbon-rich organic material was delivered to Earth — and possibly Mars as well. Such material — the dark stains we see today lining Vesta’s craters — would have helped form the very building blocks of life on our planet.

The team’s findings were published in the November/December issue of the journal Icarus.

Read more on the Max Planck Institute’s news page here, and on the NASA release here. Learn more about the Dawn mission in the video below, narrated by Leonard Nimoy.

December 14, 2012December 23, 2015 by Nancy Atkinson

Asteroid Toutatis Tumbles in New Video from NASA

NASA has compiled the radar images taken of Asteroid Toutatis during its flyby of Earth this week to create a short movie, which shows the asteroid slowly tumbling. The 64-frame movie was generated from data gathered on December 12 and 13, 2012 by NASA’s 70-meter Goldstone Deep Space Network antenna in Goldstone, California.

NASA provides more information about the video and (4179) Toutatis:

On Dec. 12, the day of its closest approach to Earth, Toutatis was about 18 lunar distances, 4.3 million miles (6.9 million kilometers) from Earth. On Dec. 13, the asteroid was about 4.4 million miles (7 million kilometers), or about 18.2 lunar distances.

The radar data images of asteroid Toutatis indicate that it is an elongated, irregularly shaped object with ridges and perhaps craters. Along with shape detail, scientists are also seeing some interesting bright glints that could be surface boulders. Toutatis has a very slow, tumbling rotational state. The asteroid rotates about its long axis every 5.4 days and precesses (changes the orientation of its rotational axis) like a wobbling, badly thrown football, every 7.4 days.

The orbit of Toutatis is well understood. The next time Toutatis will approach at least this close to Earth is in November of 2069, when the asteroid will safely fly by at about 7.7 lunar distances, or 1.8 million miles (3 million kilometers). An analysis indicates there is zero possibility of an Earth impact over the entire interval over which its motion can be accurately computed, which is about the next four centuries.

This radar data imagery will help scientists improve their understanding of the asteroid’s spin state, which will also help them understand its interior.

The resolution in the image frames is 12 feet (3.75 meters) per pixel.

Source: NASA

December 12, 2012December 23, 2015 by Nancy Atkinson

Asteroid Toutatis Tumbles by Earth: Images and Videos

Goldstone delay-Doppler radar images of Toutatis from December 11, 2012. Credit: NASA

While Asteroid 4179 Toutatis was never a threat to hit Earth during its quite-distant pass on Dec. 11-12, astronomers were keeping their instruments and eyes on this space rock to learn more about it, as well as learning more about the early solar system. Even at closest approach, 4179 Toutatis was 7 million km away or 18 times farther than the Moon. But that is close enough for radar imaging by NASA’s Goldstone Observatory, which has recently upgraded to a new digital imaging system, as well as optical imaging by other astronomers. Already, there are some preliminary findings from this 4.5-kilometer- long (3-mile-long) asteroid’s flyby.

“Toutatis appears to have a complicated internal structure,” said radar team member Michael Busch of the National Radio Astronomy Observatory. “Our radar measurements are consistent with the asteroid’s little lobe being ~15% denser than the big lobe; and they indicate 20% to 30% over-dense cores inside the two lobes.”

NASA says this raises the interesting possibility that asteroid Toutatis is actually a mash up of smaller space rocks. “Toutatis could be re-accumulated debris from an asteroid-asteroid collision in the main belt,” Busch said. The new observations will help test this idea.

Here are more images and video from Toutastis’ pass:

Adam Block from the Mount Lemmon SkyCenter/University of Arizona captured this footage:

Toutatis from Adam Block on Vimeo.

Astronomers are getting to know this asteroid, as it passes by Earth’s orbit every 4 years. It is one of the largest known potentially hazardous asteroids (PHAs), and its orbit is inclined less than half-a-degree from Earth’s. No other kilometer-sized PHA moves around the Sun in an orbit so nearly coplanar with our own. This makes it an important target for radar studies.

The team from the Remanzacco Observatory took this 120-second image of Toutatis:

Image from the ITelescope network (Nerpio, Spain) on 2012, Dec. 11.9, through a 0.15-m f/7.3 refractor + CCD. Credit: Ernesto Guido and Nick Howes/ Remanzacco Observatory.

And this was a fairly close pass for Toutatis: The next time Toutatis will approach at least this close to Earth is in November of 2069
when the asteroid will fly by at a distance of only 0.0198 AU (7.7 lunar distances).

NASA’s Goldstone radar in the Mojave Desert has been “pinging” the space rock every day starting on December 4, and will continue until the 22nd. The echoes highlight the asteroid’s topography and improve the precision with which researchers know the asteroid’s orbit.

Additionally, the Chinese Chang’e 2 spacecraft will be observing Toutatis tomorrow, on December 13, 2012 Chang’e 2 was originally launched to study the Moon but after completing its mission, Chang’e 2 departed from the L2 point in April 2012 to align itself to make a flyby of 4179 Toutatis, expected to take place at approximately 08:27 UTC on December 13.

“We already know that Toutatis will not hit Earth for hundreds of years,” said Lance Benner of NASA’s Near Earth Object Program.. “These new observations will allow us to predict the asteroid’s trajectory even farther into the future.”

Animation from Ernesto Guido and Nick Howes of 40 consecutive 10-second exposures. Credit: Ernesto Guido and Nick Howes/ Remanzacco Observatory.

NASA says the asteroid is already remarkable for the way that it spins. Unlike planets and the vast majority of asteroids, which rotate in an orderly fashion around a single axis, Toutatis travels through space “tumbling like a badly thrown football,” as Benner describes it. One of the goals of the radar observations is to learn more about the asteroid’s peculiar spin state and how it changes in response to tidal forces from the Sun and Earth.

Here’s an animation of Asteroid Toutatis compiled the live broadcast from the Slooh space camera team:

Goldstone delay-Doppler radar images of Toutatis from December 11, 2012. Credit: NASA

Sources: NASA, Remanzacco Observatory, Chang’e 2 mission

December 11, 2012December 23, 2015 by Nancy Atkinson

Close Approach Image of Asteroid 2012 XE54

Image of Asteroid 2012 XE54 taken with the the H06 ITelescope network near Mayhill, New Mexico on December 11, 2012, through a 0.25-m f/3.4 reflector + CCD. Credit: Ernesto Guido & Nick Howes, Remanzacco Observatory.

A newly discovered small asteroid named 2012 XE54 passed harmlessly by Earth early today and as predicted it was eclipsed by Earth’s shadow, causing its light to “wink out” for a short time, about 40 minutes.

Above is an image of the asteroid from Ernesto Guido and Nick Howes using a 0.25-m f/3.4 reflector + CCD with the ITelescope facility near Mayhill, New Mexico. It is a single 60-second exposure, “taken with the asteroid at magnitude ~13.2 and moving at ~630 “/min. The asteroid is trailed in the image due to its fast speed. At the moment of the close approach 2012 XE54 will move at ~ 720″/min… North is up, East is to the left,” wrote Guido and Howes on the Remanzacco Observatory website.

Below is an animation showing the movement of 2012 XE54, using three consecutive 60-second exposures. This asteroid was zipping right along at a fast pace, at a distance from Earth of about 226,000 km (141,000 miles) or about .6 lunar distances.

2012 XE54 Animation December 11, 2012, by E. Guido & N. Howes

Pasquale Tricarico of the Planetary Science Institute had predicted that the asteroid would pass through the Earth’s shadow, creating an asteroid eclipse, a rather rare event that is similar to an eclipse of the full Moon by Earth’s shadow. At 01:22 UTC on December 11 the eclipse began, and it left Earth’s shadow at 02:00 UTC. Those watching the asteroid noted that the asteroid “disappeared” from its track, and then reappeared after leaving Earth’s shadow.

“In two images taken at 01:30:16 and 01:31:18, 60sec exposure, 2012 XE54 appeared as a very faint and long track, then… nothing. In the following images there is no visible track. Wonderful!” wrote Elia Cozzi from the New Millennium Observatory, posting in the mpml asteroid research group message board.

Orbital diagram of Asteroid 2012 XE54 from JPL’s Small Body Database.

While we don’t have images to share of that event, as Guido and Howes mentioned, Peter Birtwhistle produced a lightcurve (see graph below) of the eclipse:

Tricarico wrote that the first known case of an asteroid being eclipsed by Earth’s shadow was “Asteroid 2008 TC3 which was totally eclipsed just one hour before entering Earth’s atmosphere over Sudan in 2008, and asteroid 2012 KT42 experiencing both an eclipse and a transit during the same Earth flyby in 2012.”

Guido and Howes also mentioned that their work last night was “in memory of our dear friend & colleague Giovanni Sostero.”

December 11, 2012December 23, 2015 by Nancy Atkinson

Two Asteroids Will Buzz Past Earth on December 11

Four computer generated views of Asteroid Toutatis based on Goldstone radar imagery. Via NASA

A newly discovered small asteroid named 2012 XE54 and a long-studied giant space rock named Toutatis will buzz past Earth during the next 24 hours, and astronomers are already watching the skies. While there is no danger of either hitting Earth, scientists have much to learn from both. Asteroid 2012 XE54 was discovered over the weekend on December 9 and it will safely pass between the Earth and the Moon’s orbit at a distance of about 226,000 km (141,000 miles) or about .6 lunar distances. Closest approach will be just a few hours after this article was posted, at 10:10 UTC on Dec. 11. But already an interesting event has already happened with this 28-meter-wide asteroid: it was eclipsed by Earth’s shadow. This is quite a rare event, and was visible to astronomers.

This animation shows the Sun and the Earth as observed from the asteroid 2012 XE54. If this eclipse occurs, the asteroid will be in Earth’s shadow. Animation via Pasquale Tricarico

Pasquale Tricarico of the Planetary Science Institute had predicted that the asteroid would pass through the Earth’s shadow, creating an asteroid eclipse, an event that is similar to an eclipse of the full Moon by Earth’s shadow. At 01:22 UTC on December 11 the eclipse began, and it left Earth’s shadow at 02:00 UTC. Those watching the asteroid noted that the asteroid “disappeared” from its track, and then reappeared after leaving Earth’s shadow.

We hope to have images of the event when they become available.

4179 Toutatis, with a shape that has been described as a “malformed potato” will pass at a large distance of 6.9 million kilometers (4.3 million miles) away from Earth, or more than 18 times the distance from the Earth to the Moon.

It is a biggie, though at 4.46 kilometers (2.7 miles) long and 2.4 kilometers (1.5 miles) wide, and is considered a potentially hazardous asteroid because it makes repeated passes by the Earth, about every four years. In comparison, the asteroid that is thought to have destroyed the dinosaurs was approximately 10 km (6 miles) wide.

It’s closest pass will be covered by the Slooh Space Camera on Tuesday, December 11th, with several live shows on Slooh.com, free to the public, starting at 20:00 UTC (12 PM PST / 3 PM EST, find international times here — accompanied by real-time discussions with Slooh President, Patrick Paolucci, and Astronomy Magazine columnist, Bob Berman.

At its maximum brightness, Toutatis might be barely visible through binoculars, but should be very bright through Slooh telescopes at its being tracked.

“We will be tracking Asteroid Toutatis live from two observatory locations – Canary Islands, off the coast of Africa and Arizona,” said Patrick Paolucci, President at Slooh.

Astronomers are interested in this returning asteroid to try and figure out what the asteroid is made of. Also by refining a model of the asteroid’s rotation, they’ll get a better idea of its composition, thereby gaining a greater understanding of the early solar system.

Lance Benner from JPL said that this asteroid is tumbling slowly, but with a complex motion.

“It’s a very peculiar rotation state,” Benner said. “It rotates very slowly and it tumbles in a manner somewhat similar to the way a football tumbles if you screw up a long pass.”

Sources: Slooh, Earth-Sky blog, JPL Small Body database, Planetary Science Institute